The present invention relates to a breather system for a crankcase of an internal combustion engine of the type which separates oil drops or mist from blow-by gases. The blow-by gases are routed to the intake air line of an engine to eliminate the discharge of combustion gases into the environment. Separated oil is routed back to the oil pan.
Ideally, the pressure within an internal combustion engine crankcase should be maintained at a level equal to or slightly less than atmospheric pressure to prevent external oil leakage through the various gasketed joints, such as that between the valve cover and the cylinder head. Combustion gases are generated during the operation of an internal combustion engine. A small amount of these gases leaks past the piston seals, valve stems seals, and turbochargers of the internal combustion engine. Because of the “blow-by” gases, the crankcase pressure will inherently rise, promoting leakage of oil from the crankcase. These gases, commonly referred to in the art as “blow-by” gases, need to be released.
Environmental considerations suggest that the blow-by gases in the crankcase be vented back to the combustion chamber rather than being released to the atmosphere. Accordingly, it is known to scavenge the crankcase of blow-by gases by connecting the crankcase to the engine air intake.
Blow-by gases that are released from the crankcase carry combustion by-products and oil mist caused by splashing of the engine's moving components within the crankcase and the oil pan. It is known to substantially remove the oil mist from the blow-by gas prior to introduction into the intake air system. An apparatus that removes oil mist from blow-by gases is commonly referred to as a “breather.” Known breathers include breathers that include a stack of conical disks that spin at a high speed to fling heavier oil against a wall of the breather and allow gas to pass though the breather. Centrifuge type separators are disclosed for example in U.S. Pat. Nos. 7,235,177 and 6,139,595. Other types of breathers include filters such as described in U.S. Pat. Nos. 6,478,019, 6,354,283; 6,530,969; 5,113,836; swirl chambers or cyclone separators, such as described in U.S. Pat. Nos. 6,860,915; 5,239,972; or impactors, such as described in U.S. Pat. Nos. 7,258,111; 7,238,216 5,024,203. Each type of breather has advantages and limitations.
The present inventor has recognized that it would be desirable to provide a breather system that is more economical to produce and more effective in operation than existing breather systems.